day15-python之变量和递归

1.局部变量与全局变量

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-

 # name='lhf'
 # def change_name():
 #     global name
 #     name='帅了一比'
 #     print('change_name',name)
 #
 #
 # change_name()
 # print(name)

 # name='lhf'
 #
 # def change_name():
 #     name1='帅了一比'
 #     name2='帅了一比'
 #     name3='帅了一比'
 #     print('change_name',name)
 #
 # globals

 # NAME = "杠娘"
 #
 # def yangjian():
 #     global NAME
 #     NAME = "小东北"
 #     print('我要搞', NAME)
 #
 # def qupengfei():
 #     NAME = "基"
 #     print('我要搞', NAME)
 #
 # yangjian()
 # qupengfei()

 # NAME = "产品经理"
 #
 # def yangjian():
 #     # NAME = "史正文"
 #     global NAME # 已经声明，ＮＡＭＥ就是全局的的那个变量
 #     print('我要搞', NAME)
 #     NAME = "小东北"  # 修改 全局的变量
 #     print('我要搞', NAME)
 #
 # def qupengfei():
 #     NAME = "基"
 #     print('我要搞', NAME)

 # 如果函数的内容无global关键字，
 #   - 有声明局部变量
 # NAME = ["产品经理","廖波湿"]
 # def qupengfei():
 #     NAME = "自己"
 #     print('我要搞', NAME)
 # qupengfei()
 #   - 无声明局部变量
 # NAME = ["产品经理","廖波湿"]
 # def qupengfei():
 #     NAME.append('XXOO')
 #     print('我要搞', NAME)
 # qupengfei()

 # 如果函数的内容有global关键字
 #   - 有声明局部变量
 # NAME = ["产品经理","廖波湿"]
 # def qupengfei():
 #     global NAME
 #     NAME = "自己"
 #     print('我要搞', NAME)
 # qupengfei()
         # 错误示例
 # NAME = ["产品经理","廖波湿"]
 # def qupengfei():
 #     NAME = "自己"
 #     global NAME
 #     print('我要搞', NAME)
 # qupengfei()
 #   - 无声明局部变量
 # NAME = ["产品经理","廖波湿"]
 # def qupengfei():
 #     global NAME
 #     NAME = ["阿毛"]
 #     NAME.append('XXOO')
 #     print('我要搞', NAME)
 # qupengfei()

 ######## 全局变量变量名大写
 ######## 局部变量变量名小写

 # 优先读取局部变量，能读取全局变量，无法对全局变量重新赋值 NAME=“fff”，
 #     但是对于可变类型，可以对内部元素进行操作
 # 如果函数中有global关键字，变量本质上就是全局的那个变量，可读取可赋值 NAME=“fff”
 # qupengfei()
 # yangjian()

 # NAME = ["产品经理","廖波湿"]
 #
 # def yangjian():
 #     # NAME = "史正文"
 #     global NAME # 已经声明，ＮＡＭＥ就是全局的的那个变量
 #     print('我要搞', NAME)
 #     NAME = "小东北"  # 修改 全局的变量
 #     print('我要搞', NAME)
 #
 # def qupengfei():
 #     # NAME = "aS"
 #     NAME.append('天扎龙')
 #     print('我要搞', NAME)
 #
 # yangjian()

 # NAME = ["产品经理","廖波湿"]
 # def qupengfei():
 #     name = "自己"
 #     global NAME
 #     print('我要搞', NAME)
 # qupengfei()

 # NAME = '海风'
 #
 # def huangwei():
 #     name = "黄伟"
 #     print(name)
 #     def liuyang():
 #         name = "刘洋"
 #         print(name)
 #         def nulige():
 #             name = '沪指花'
 #             print(name)
 #         print(name)
 #         nulige()
 #     liuyang()
 #     print(name)
 #
 # huangwei()  # 黄伟 刘洋 刘洋 沪指花 黄伟

 # name = "刚娘"
 #
 # def weihou():
 #     name = "陈卓"
 #     def weiweihou():
 #         nonlocal name   # nonlocal，指定上一级变量，如果没有就继续往上直到找到为止
 #         name = "冷静"
 #
 #     weiweihou()
 #     print(name)
 #
 # print(name)
 # weihou()
 # print(name)
 # 刚娘
 # 冷静
 # 刚娘

2.前向引用

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-

 # def foo():
 #     print('from foo')
 #     bar()
 #
 # foo()

 # def bar():
 #     print('from bar')
 # def foo():
 #     print('from foo')
 #     bar()
 #
 # foo()

 # def foo():
 #     print('from foo')
 #     bar()
 #
 # def bar():
 #     print('from bar')
 # foo()

 # def foo():
 #     print('from foo')
 #     bar()
 #
 # foo()
 #
 # def bar():
 #     print('from bar')

3.测试

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 name='海风'
 def huangwei():
     name = "黄伟"
     print(name)
     def liuyang():
         name = "刘洋"
         print(name)
         def nulige():
             name = '炉指花'
             print(name)
         print(name)
         nulige()
     liuyang()
     print(name)

 print(name)
 huangwei()
 print(name)  # 海风 黄伟 刘洋 刘洋 炉指花 黄伟 海风

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 def calc(n):
     print(n)
     if int(n / 2) == 0: # 10/2  5/2  2/2
         return n
     res=calc(int(n / 2))
     return res

 calc(10)#   10 5 2 1

4.递归

 #!/usr/bin/env python
 # -*- coding:utf-8 -*-
 # def calc(n):
 #     print(n)
 #     if int(n / 2) == 0:
 #         return n
 #     res=calc(int(n / 2))
 #     return res
 #
 #
 # res=calc(10)
 # print(res)

 # while True:
 #     print(10)

 # import time
 #
 # person_list=['alex','wupeiqi','linhaifeng','zsc']
 # def ask_way(person_list):
 #     print('-'*60)
 #     if len(person_list) == 0:
 #         return '根本没人知道'
 #     person=person_list.pop(0)
 #     if person == 'linhaifeng':
 #         return '%s说:我知道,老男孩就在沙河汇德商厦,下地铁就是' %person
 #
 #     print('hi 美男[%s],敢问路在何方' % person)
 #     print('%s回答道:我不知道,但念你慧眼识猪,你等着,我帮你问问%s...' % (person, person_list))
 #     time.sleep(1)
 #     res=ask_way(person_list)
 #
 #
 #     print('%s问的结果是: %res' %(person,res))
 #     return res
 #
 # res=ask_way(person_list)
 # print(res)
 # 我          来英                杨建         是征文
 # res等沙河      res等沙河       res等 沙河      return ‘沙河’
 #                 print          printres

 import time
 res=time.sleep(10)
 print('----------->')